<template>
<div>
    <router-link 
    tag="div" 
    to="/" 
    class="header-abs"
    v-show="showAbs">
         <div class='iconfont header-abs-back'>&#xe624;</div>
    </router-link>
    <div 
        class="header-fixed" 
        v-show="!showAbs"
        :style="opacityStyle">
        <router-link to="/">
            <div class='iconfont header-fixed-back'>&#xe624;</div>
        </router-link>
        景点详情
    </div>
</div>
</template>

<script>
export default {
    name: 'DetailHeader',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handleScroll () {
            const top = document.documentElement.scrollTop
            if (top > 60 ) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1: opacity
                this.opacityStyle = { opacity }
                this.showAbs = false
            } else {
                this.showAbs =true
            }
        }
    },
    activated () {
        window.addEventListener('scroll', this.handleScroll)
    },
    deactivated () {
        window.removeEventListener('scroll', this.handleScroll)
    }
}
</script>

<style lang="stylus" scoped>
  @import '~@/assets/styles/varibles.styl'
    .header-abs
        position : absolute
        left: .3rem
        top : .3rem
        width : 1.5rem
        height : 1.5rem
        line-height : .8rem
        border-radius : .8rem
        text-align : center
        background : rgba(0, 0, 0, .8)
        .header-abs-back
            padding-top : .3rem
            color : #fff
            font-size : .4rem
    .header-fixed
        z-index : 2
        position : fixed
        top : 0
        left : 0
        right : 0
        height : 1.95rem
        line-height : 1.95rem
        text-align : center
        color : #fff
        background : $bgColor
        find-size : .32rem
        .header-fixed-back
            position : absolute
            top : 0
            left : 0
            width : .64rem
            text-align : center
            font-size : .4rem
            color : #fff    
</style>